Stock Based Compensation (Outstanding Employee Deferred Stock Awards) (Details) - $ / shares		May. 01, 2015	May. 09, 2014	Jan. 03, 2014	Apr. 02, 2013	Mar. 31, 2016	Dec. 31, 2015
Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant Date Fair Value						$ 18.83	$ 18.67
Unvested Shares						935,201	959,446
Deferred Stock Awards [Member] | Deferred Stock Award, Granted April 2, 2013 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Net Shares Granted	[1]				118,174
Grant Date Fair Value					$ 19.47
Unvested Shares						37,084
Deferred Stock Awards [Member] | Deferred Stock Award, Granted April 2, 2013 [Member] | Share-based Compensation Award, Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage					25.00%
Deferred Stock Awards [Member] | Deferred Stock Award, Granted April 2, 2013 [Member] | Share-based Compensation Award, Tranche Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage					25.00%
Deferred Stock Awards [Member] | Deferred Stock Award, Granted April 2, 2013 [Member] | Share-based Compensation Award, Tranche Three [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage					25.00%
Deferred Stock Awards [Member] | Deferred Stock Award, Granted April 2, 2013 [Member] | Share-based Compensation Award, Tranche Four [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage					25.00%
Deferred Stock Awards [Member] | Deferred Stock Award, Granted January 3, 2014 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Net Shares Granted	[1]			87,706
Grant Date Fair Value				$ 16.45
Unvested Shares						62,004
Deferred Stock Awards [Member] | Deferred Stock Award, Granted January 3, 2014 [Member] | Share-based Compensation Award, Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage				20.00%
Deferred Stock Awards [Member] | Deferred Stock Award, Granted January 3, 2014 [Member] | Share-based Compensation Award, Tranche Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage				20.00%
Deferred Stock Awards [Member] | Deferred Stock Award, Granted January 3, 2014 [Member] | Share-based Compensation Award, Tranche Three [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage				20.00%
Deferred Stock Awards [Member] | Deferred Stock Award, Granted January 3, 2014 [Member] | Share-based Compensation Award, Tranche Four [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage				20.00%
Deferred Stock Awards [Member] | Deferred Stock Award, Granted January 3, 2014 [Member] | Share-based Compensation Award, Tranche Five [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage				20.00%
Deferred Stock Awards [Member] | Deferred Stock Award, Granted May 9, 2014 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Net Shares Granted	[1]		162,517
Grant Date Fair Value			$ 18.47
Unvested Shares						93,659
Deferred Stock Awards [Member] | Deferred Stock Award, Granted May 9, 2014 [Member] | Share-based Compensation Award, Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage			25.00%
Deferred Stock Awards [Member] | Deferred Stock Award, Granted May 9, 2014 [Member] | Share-based Compensation Award, Tranche Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage			25.00%
Deferred Stock Awards [Member] | Deferred Stock Award, Granted May 9, 2014 [Member] | Share-based Compensation Award, Tranche Three [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage			25.00%
Deferred Stock Awards [Member] | Deferred Stock Award, Granted May 9, 2014 [Member] | Share-based Compensation Award, Tranche Four [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage			25.00%
Deferred Stock Awards [Member] | Deferred Stock Award, Granted May 1, 2015 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Net Shares Granted	[1]	271,970
Grant Date Fair Value		$ 17.59
Unvested Shares						218,971
Deferred Stock Awards [Member] | Deferred Stock Award, Granted May 1, 2015 [Member] | Share-based Compensation Award, Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage		25.00%
Deferred Stock Awards [Member] | Deferred Stock Award, Granted May 1, 2015 [Member] | Share-based Compensation Award, Tranche Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage		25.00%
Deferred Stock Awards [Member] | Deferred Stock Award, Granted May 1, 2015 [Member] | Share-based Compensation Award, Tranche Three [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage		25.00%
Deferred Stock Awards [Member] | Deferred Stock Award, Granted May 1, 2015 [Member] | Share-based Compensation Award, Tranche Four [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage		25.00%
Performance Share Program Award [Member] | Performance Share Program Award, Granted May 9, 2014 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Net Shares Granted	[1]		0
Grant Date Fair Value			$ 22.00
Unvested Shares	[2]					179,822
Performance Share Program Award [Member] | Performance Share Program Award, Granted May 1, 2015 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Net Shares Granted	[1]	0
Grant Date Fair Value		$ 18.42
Unvested Shares	[2]					343,661

[1] Amounts reflect the total grant to employees, net of shares surrendered upon vesting to satisfy required minimum tax withholding obligations through March 31, 2016.

[2] Estimated based on Piedmont's cumulative TSR for the respective performance period through March 31, 2016. Share estimates are subject to change in future periods based on both Piedmont's and its peers' stock performance and dividends paid.